Implements driver for the Ambient/UV Light sensor LTR390. The driver exposes two ways of getting sensor readings: 1. Raw UV Counts directly from the sensor 2. The computed UV Index value with a percision of 2 decimal places [NOTE] Ambient light sensing has not been implemented yet. Driver tested on RPi Zero 2W Datasheet: https://optoelectronics.liteon.com/upload/download/DS86-2015-0004/LTR-390UV_Final_%20DS_V1%201.pdf Signed-off-by: Anshul Dalal <anshulusr@xxxxxxxxx> --- Changes for v3: - Formatted header includes - Replaced instances of LTR390_DEVICE_NAME with "ltr390" - Use shorthand macro 'guard' for mutex - Replace instances of `dev_err` followed by a return with `dev_err_probe` - Separate channel for UV Index into a IIO_CHAN_INFO_RAW and _SCALE - Remove unused IIO_INTENSITY channel - Warn on invalid product id instead of exiting - Changed `ltr390_id_table` to `ltr390_of_table` [TYPO] > MODULE_DEVICE_TABLE(of, ltr390_of_table) - Removed of_match_ptr Changes for v2: - Fixed typo in `LTR390_FRACTIONAL_PRECISION` - Added of_device_id Previous versions: v2: https://lore.kernel.org/lkml/20231117074554.700970-2-anshulusr@xxxxxxxxx/ v1: https://lore.kernel.org/lkml/20231109090456.814230-2-anshulusr@xxxxxxxxx/ --- MAINTAINERS | 7 ++ drivers/iio/light/Kconfig | 11 +++ drivers/iio/light/Makefile | 1 + drivers/iio/light/ltr390.c | 195 +++++++++++++++++++++++++++++++++++++ 4 files changed, 214 insertions(+) create mode 100644 drivers/iio/light/ltr390.c diff --git a/MAINTAINERS b/MAINTAINERS index 81d5fc0bba68..c9f2238673f0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12484,6 +12484,13 @@ S: Maintained W: http://linux-test-project.github.io/ T: git https://github.com/linux-test-project/ltp.git +LTR390 AMBIENT/UV LIGHT SENSOR DRIVER +M: Anshul Dalal <anshulusr@xxxxxxxxx> +L: linux-iio@xxxxxxxxxxxxxxx +S: Maintained +F: Documentation/devicetree/bindings/iio/light/liteon,ltr390.yaml +F: drivers/iio/light/ltr390.c + LYNX 28G SERDES PHY DRIVER M: Ioana Ciornei <ioana.ciornei@xxxxxxx> L: netdev@xxxxxxxxxxxxxxx diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig index 45edba797e4c..61993ae79afe 100644 --- a/drivers/iio/light/Kconfig +++ b/drivers/iio/light/Kconfig @@ -347,6 +347,17 @@ config SENSORS_LM3533 changes. The ALS-control output values can be set per zone for the three current output channels. +config LTR390 + tristate "LTR-390UV-01 ambient light and UV sensor" + depends on I2C + select REGMAP_I2C + help + If you say yes here you get support for the Lite-On LTR-390UV-01 + ambient light and UV sensor. + + This driver can also be built as a module. If so, the module + will be called ltr390. + config LTR501 tristate "LTR-501ALS-01 light sensor" depends on I2C diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile index c0db4c4c36ec..550f8b408bc2 100644 --- a/drivers/iio/light/Makefile +++ b/drivers/iio/light/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_SENSORS_ISL29028) += isl29028.o obj-$(CONFIG_ISL29125) += isl29125.o obj-$(CONFIG_JSA1212) += jsa1212.o obj-$(CONFIG_SENSORS_LM3533) += lm3533-als.o +obj-$(CONFIG_LTR390) += ltr390.o obj-$(CONFIG_LTR501) += ltr501.o obj-$(CONFIG_LTRF216A) += ltrf216a.o obj-$(CONFIG_LV0104CS) += lv0104cs.o diff --git a/drivers/iio/light/ltr390.c b/drivers/iio/light/ltr390.c new file mode 100644 index 000000000000..49dfd2bdd1ee --- /dev/null +++ b/drivers/iio/light/ltr390.c @@ -0,0 +1,195 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IIO driver for Lite-On LTR390 ALS and UV sensor + * (7-bit I2C slave address 0x53) + * + * Based on the work of: + * Shreeya Patel and Shi Zhigang (LTRF216 Driver) + * + * Copyright (C) 2023 Anshul Dalal <anshulusr@xxxxxxxxx> + * + * Datasheet: + * https://optoelectronics.liteon.com/upload/download/DS86-2015-0004/LTR-390UV_Final_%20DS_V1%201.pdf + * + * TODO: + * - Support for configurable gain and resolution + * - Sensor suspend/resume support + * - Add support for reading the ALS + * - Interrupt support + */ + +#include <linux/i2c.h> +#include <linux/math.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/regmap.h> + +#include <linux/iio/iio.h> + +#include <asm/unaligned.h> + +#define LTR390_MAIN_CTRL 0x00 +#define LTR390_PART_ID 0x06 +#define LTR390_UVS_DATA 0x10 + +#define LTR390_SW_RESET BIT(4) +#define LTR390_UVS_MODE BIT(3) +#define LTR390_SENSOR_ENABLE BIT(1) + +#define LTR390_PART_NUMBER_ID 0xb + +/* + * At 20-bit resolution (integration time: 400ms) and 18x gain, 2300 counts of + * the sensor are equal to 1 UV Index [Datasheet Page#8]. + * + * For the default resolution of 18-bit (integration time: 100ms) and default + * gain of 3x, the counts/uvi are calculated as follows: + * 2300 / ((3/18) * (100/400)) = 95.83 + */ +#define LTR390_COUNTS_PER_UVI 96 + +/* + * Window Factor is needed when the device is under Window glass with coated + * tinted ink. This is to compensate for the light loss due to the lower + * transmission rate of the window glass and helps * in calculating lux. + */ +#define LTR390_WINDOW_FACTOR 1 + +struct ltr390_data { + struct regmap *regmap; + struct i2c_client *client; + /* Protects device from simulataneous reads */ + struct mutex lock; +}; + +static const struct regmap_config ltr390_regmap_config = { + .name = "ltr390", + .reg_bits = 8, + .reg_stride = 1, + .val_bits = 8, +}; + +static int ltr390_register_read(struct ltr390_data *data, u8 register_address) +{ + struct device *dev = &data->client->dev; + int ret; + u8 recieve_buffer[3]; + + guard(mutex)(&data->lock); + + ret = regmap_bulk_read(data->regmap, register_address, recieve_buffer, + sizeof(recieve_buffer)); + if (ret) + return dev_err_probe(dev, ret, + "failed to read measurement data"); + + return get_unaligned_le24(recieve_buffer); +} + +static int ltr390_read_raw(struct iio_dev *iio_device, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + int ret; + struct ltr390_data *data = iio_priv(iio_device); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = ltr390_register_read(data, LTR390_UVS_DATA); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = LTR390_WINDOW_FACTOR; + *val2 = LTR390_COUNTS_PER_UVI; + return IIO_VAL_FRACTIONAL; + default: + return -EINVAL; + } +} + +static const struct iio_info ltr390_info = { + .read_raw = ltr390_read_raw, +}; + +static const struct iio_chan_spec ltr390_channel = { + .type = IIO_UVINDEX, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) +}; + +static int ltr390_probe(struct i2c_client *client) +{ + struct ltr390_data *data; + struct iio_dev *indio_dev; + struct device *dev; + int ret, part_number; + + dev = &client->dev; + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + + data->regmap = devm_regmap_init_i2c(client, <r390_regmap_config); + if (IS_ERR(data->regmap)) + return dev_err_probe(dev, PTR_ERR(data->regmap), + "regmap initialization failed\n"); + + data->client = client; + mutex_init(&data->lock); + + indio_dev->info = <r390_info; + indio_dev->channels = <r390_channel; + indio_dev->num_channels = 1; + indio_dev->name = "ltr390"; + + ret = regmap_read(data->regmap, LTR390_PART_ID, &part_number); + if (ret) + return dev_err_probe(dev, ret, + "failed to get sensor's part id\n"); + /* Lower 4 bits of `part_number` change with hardware revisions */ + if (part_number >> 4 != LTR390_PART_NUMBER_ID) + dev_info(dev, "received invalid product id: 0x%x", part_number); + dev_dbg(dev, "LTR390, product id: 0x%x\n", part_number); + + /* reset sensor, chip fails to respond to this, so ignore any errors */ + regmap_set_bits(data->regmap, LTR390_MAIN_CTRL, LTR390_SW_RESET); + + /* Wait for the registers to reset before proceeding */ + usleep_range(1000, 2000); + + ret = regmap_set_bits(data->regmap, LTR390_MAIN_CTRL, + LTR390_SENSOR_ENABLE | LTR390_UVS_MODE); + if (ret) + return dev_err_probe(dev, ret, "failed to enable the sensor\n"); + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct i2c_device_id ltr390_id[] = { + { "ltr390" }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(i2c, ltr390_id); + +static const struct of_device_id ltr390_of_table[] = { + { .compatible = "liteon,ltr390" }, + { /* Sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ltr390_of_table); + +static struct i2c_driver ltr390_driver = { + .driver = { + .name = "ltr390", + .of_match_table = ltr390_of_table, + }, + .probe = ltr390_probe, + .id_table = ltr390_id, +}; +module_i2c_driver(ltr390_driver); + +MODULE_AUTHOR("Anshul Dalal <anshulusr@xxxxxxxxx>"); +MODULE_DESCRIPTION("Lite-On LTR390 ALS and UV sensor Driver"); +MODULE_LICENSE("GPL"); -- 2.42.1
